<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            background-color: red;
            width: 200px;
            height: 200px;
            /* border: 1px solid red; */
        }
    </style>
</head>
<body>
    <input type="button" value="按钮" onclick="test()">
    <div id="myNo1">
        
    </div>
    <script>
        function test()
        {
            var num=1;
            var a= document.getElementById('myNo1').style.border="5px solid green"
            var a= document.getElementById('myNo1').style.backgroundColor="blue"
            console.log(a)
        }
    </script>
</body>
</html>